Sir Tom Jones has postponed two US concerts on the advice of his doctor after being struck by “a bad case of the flu”.

The 86-year-old Welsh singer said he is “truly sorry” following the decision.

Sir Tom is part-way through his Come Gather Round World Tour, which began this summer with dates across the UK and Europe before moving on to a run of shows in North America.

His Monday concert in Los Angeles and Tuesday's show in San Diego have both been pushed back.

Announcing the news on Instagram, he wrote: “I’ve had a great time these last few weeks, completing 20 shows and singing for wonderful audiences across the USA, but unexpectedly I’ve been hit with a bad case of the flu.

“Following doctor’s advice, I unfortunately have to reschedule tonight’s show in Los Angeles and tomorrow’s show in San Diego.”

Tom Jones says he is currently struggling with a bout of flu (Jane Barlow/PA Wire)

New dates have been set for both performances.

The San Diego concert will now take place at The Rady Shell at Jacobs…